The present invention relates to orientation sensing systems for conveyed articles having a "right" or "wrong" conveyed orientation, and more specifically relates to orientation sensing systems for rail tie plates or the like, which could be used in conjunction with a tie plate handling and positioning system.
Tie plates are used to secure rails to railroad ties and comprise a generally flat steel plate with a substantially flat bottom, spike holes and a top having rail securing ribs. The tie plate top is angled to provide a rail seat canted inwardly, with more mass located on the field side of the plate to compensate for the force distribution of trains negotiating curves at high speed.
In the process of reconditioning railroads, the existing rail is removed along with the tie plates, the ties are replaced or resurfaced, and the track bed is refurbished. Before new rails are laid, replacement or recycled tie plates must be accurately positioned upon the ties.
Tie plate replacement is a cumbersome and labor intensive operation, due to the significant weight of the individual plates (18-36 pounds each) and the rapid rate at which they must be positioned to keep up with the other operations of track reconditioning, most of which are largely automated.
Previous attempts at automating the tie plate setting operation have resulted in devices largely concerned with the actual placement of the plates upon the ties. These prior art setters depended upon a supply of plates which had already been manually oriented, either on or off-site. On site, plates may be prepositioned along the shoulder of the track bed, or carried in a gondola to be fed via conveyors to the plate setting device. However, the rapid rate of 30 to 40 plates per minute at which automatic tie plate setters must operate to keep up with the other automated track maintenance equipment requires extensive pre-placement manual handling and sorting of plates. It has been estimated that a member of a plate feeding crew will handle 150,000 pounds per eight hour shift.
Consequently, it is an object of the present invention to provide a plate orientation sensing system to be used in conjunction with an automated plate setter that substantially reduces the amount of manual plate handling required by conventional devices.
It is a further object of the present invention to provide an automatic plate orientation sensing system which has the capability of determining whether plates are right side up or upside down.
It is an additional object of the present invention to provide an automatic plate orientation sensing device which is capable of sensing the orientation of tie plates randomly located across the width of a conveyor surface.
It is a still further object of the present invention to provide an automatic plate orientation sensing system capable of acting in conjunction with an automatic plate reorienting apparatus to properly orient upside down plates.